Error Estimates Of Mixed Finite Element Methods For Optimal Boundary Control Problems

In this paper,we investigate the error estimates for the optimal control problems.In gen-eral using finite element method solves optimal control problems for the variational prob-lems of primal variable, because we add the gradient of the state variables on objective functional,so we can cosider error estimates of mixed finite element and the posteriori error estimates about this problem.In this case we choose Raviart-Thomas element,and control variables is picewise polynomials of order k.Under the special constraint set,we derive error estimates about intermediate error,the mixed finite elemnt error and the posteriori error.